<template>
  <div class="app-container">
    <!-- 课程信息表单 -->
    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>
      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>
      <!-- 所属分类：级联下拉列表 -->
      <el-form-item label="课程类别">
        <!-- 一级分类 -->
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="请选择"
          @change="subjectChanged">
          <el-option
            v-for="subject in subjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="请选择">
          <el-option
            v-for="subject in subjectLevelTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>
      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>
      <!-- 课程简介-->
      <el-form-item label="课程简介">
        <el-input v-model="courseInfo.description" type="textarea" rows="5"/>
      </el-form-item>
      <!-- 课程封面 -->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleCoverSuccess"
          :before-upload="beforeCoverUpload"
          :on-error="handleCoverError"
          :action="BASE_API+'/admin/vod/file/upload'"
          class="cover-uploader">
          <img v-if="courseInfo.cover" :src="courseInfo.cover">
          <i v-else class="el-icon-plus avatar-uploader-icon"/>
        </el-upload>
      </el-form-item>
      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>
    </el-form>

    <div style="text-align:center">
      <el-button :disabled="saveBtnDisabled" type="primary" @click="saveAndNext()">保存并下一步</el-button>
    </div>
  </div>
</template>
<script>

    import courseApi from '@/api/vod/course'
    import teacherApi from '@/api/vod/teacher'
    import subjectApi from '@/api/vod/subject'

    export default {
        data() {
            return {
                BASE_API: 'http://localhost:9001',
                saveBtnDisabled: false, // 按钮是否禁用
                courseInfo: {// 表单数据
                    price: 0,
                    lessonNum: 0,
                    // 以下解决表单数据不全时insert语句非空校验
                    teacherId: '',
                    subjectId: '',
                    subjectParentId: '',
                    cover: '',
                    description: ''
                },
                teacherList: [], // 讲师列表
                subjectList: [], // 一级分类列表
                subjectLevelTwoList: []// 二级分类列表
            }
        },
        created() {
            if (this.$parent.courseId) { // 回显
                this.fetchCourseInfoById(this.$parent.courseId)
            } else { // 新增
                // 初始化分类列表
                this.initSubjectList()
            }
            // 获取讲师列表
            this.initTeacherList()
        },
        methods: {

            // 获取课程信息
            fetchCourseInfoById(id) {
                courseApi.getCourseInfoById(id).then(response => {
                    this.courseInfo = response.data
                    // 初始化分类列表
                    subjectApi.getChildList(0).then(response => {
                        this.subjectList = response.data
                        // 填充二级菜单：遍历一级菜单列表，
                        this.subjectList.forEach(subject => {
                            // 找到和courseInfo.subjectParentId一致的父类别记录
                            if (subject.id === this.courseInfo.subjectParentId) {
                                // 拿到当前类别下的子类别列表，将子类别列表填入二级下拉菜单列表
                                subjectApi.getChildList(subject.id).then(response => {
                                    this.subjectLevelTwoList = response.data
                                })
                            }
                        })
                    })
                })
            },
            // 保存并下一步
            saveAndNext() {
                this.saveBtnDisabled = true
                if (!this.$parent.courseId) {
                    this.saveData()
                } else {
                    this.updateData()
                }
            },
            // 修改
            updateData() {
                courseApi.updateCourseInfoById(this.courseInfo).then(response => {
                    this.$message.success(response.message)
                    this.$parent.courseId = response.data // 获取courseId
                    this.$parent.active = 1 // 下一步
                })
            },

            // 获取讲师列表
            initTeacherList() {
                teacherApi.list().then(response => {
                    this.teacherList = response.data
                })
            },

            // 初始化分类列表
            initSubjectList() {
                subjectApi.getChildList(0).then(response => {
                    this.subjectList = response.data
                })
            },

            // 选择一级分类，切换二级分类
            subjectChanged(value) {
                subjectApi.getChildList(value).then(response => {
                    this.courseInfo.subjectId = ''
                    this.subjectLevelTwoList = response.data
                })
            },

            // 上传成功回调
            handleCoverSuccess(res, file) {
                this.courseInfo.cover = res.data
            },

            // 上传校验
            beforeCoverUpload(file) {
                const isJPG = file.type === 'image/jpeg'
                const isLt2M = file.size / 1024 / 1024 < 2
                if (!isJPG) {
                    this.$message.error('上传头像图片只能是 JPG 格式!')
                }
                if (!isLt2M) {
                    this.$message.error('上传头像图片大小不能超过 2MB!')
                }
                return isJPG && isLt2M
            },

            // 错误处理
            handleCoverError() {
                console.log('error')
                this.$message.error('上传失败2')
            },

            // 保存并下一步
            saveAndNext() {
                this.saveBtnDisabled = true
                if (!this.$parent.courseId) {
                    this.saveData()
                } else {
                    //this.updateData()
                }
            },

            // 保存
            saveData() {
                courseApi.saveCourseInfo(this.courseInfo).then(response => {
                    this.$message.success(response.message)
                    this.$parent.courseId = response.data // 获取courseId
                    this.$parent.active = 1 // 下一步
                })
            }
        }
    }
</script>
<style scoped>
  .tinymce-container {
    position: relative;
    line-height: normal;
  }
  .cover-uploader .avatar-uploader-icon {
    border: 1px dashed #d9d9d9;
    border-radius: 6px;
    cursor: pointer;
    position: relative;
    overflow: hidden;

    font-size: 28px;
    color: #8c939d;
    width: 640px;
    height: 357px;
    line-height: 357px;
    text-align: center;
  }
  .cover-uploader .avatar-uploader-icon:hover {
    border-color: #409EFF;
  }
  .cover-uploader img {
    width: 640px;
    height: 357px;
    display: block;
  }
</style>
